1. Field of the Invention
The present invention relates generally to sealing devices, and more particularly to an improved expansion joint seal used to protect areas between abutting building surfaces from moisture and foreign material, that allows independent movement of each building surface.
2. Description of the Relevant Art
Expansion-type joint seals of a wide variety have been used in construction for some time. Typically, when large structures are constructed allowance for expansion and contraction of the building materials due to thermal variations and motion of the structure due to seismic activity and climatic conditions (i.e. wind) must be made. A common method for making such allowances is to construct the structure leaving gaps, called joints, in sections of the structure. In this method discrete sections of the structure are left free to move independently of one another so as to distribute any expansion or contraction of the building material, or other motion due to seismic activity, climatic conditions or the like.
When joints are provided in the structure steps must be taken to isolate the internal environment of the structure from the external environment. It is especially important to seal the internal environment from water, dirt and other foreign material which may affect heating, ventilation, electrical interconnection, interior fixtures and the like. A requirement of any seal used in such cases is that it be capable of expanding and contracting to accommodate motion of the structure while maintaining its imperviousness.
In the past such seals have comprised single strips of weather resistant synthetic rubber, such as neoprene, extended between opposing structural surfaces, such as that described in U.S. Pat. No. 4,290,713 (Brown et al.). Effective integrity of the seal over significant variations in joint width is presently preferably achieved by contouring the seal in an accordion-like fashion, or forming the seal with a serpentine cross section. Such a configuration is contrary to the aesthetic desire to present as flat and uniform a surface as possible of increased importance when the seal is used in interior applications. One variation on the basic concept includes utilizing double seals to achieve improved flexibility of the seal while presenting an aesthetically pleasing surface. A manifold contoured rear seal designed to maximize seal integrity and a minimally contoured face seal designed for aesthetic appeal are typically provided. The disadvantage of the double seal arrangement is that the rear seal must be fully installed before the front seal may be installed Thus, the installation time involved in the double seal arrangement is at least doubled. Whereas use of a prior art single seal is a trade-off between aesthetic appearance and integrity of the seal, prior art double seal devices are a trade-off between aesthetic appearance and ease and speed of installation.
The expansion joint seal according to the present invention provides a pleasing aesthetic appearance, integrity of seal and minimal installation time as well as: dual durometer seals, harder at those points where the seal is secured to the structure's surfaces; lower cost of production, only one die required for fabricating the seal; and, greatly improved resistance to deformation and sagging in both vertical and horizontal installations. The frame, mounted to the building surfaces, to which the seal is attached also provides the advantages of allowing securing of the frame to the building surface using a diagonally installed screw, tie or the like, especially helpful in narrow installations, and accommodations for mounting the frame to non-flush surfaces.